Brake head and shoe.



,. B. P. HYSELL & R. M. GAVBDO.

BRAKE HEAD AND SHOE.

APPLICATION FILED 00117, 1909.

Patented. May 31, 1910;

BENJAMIN F. I-IYSELL AND ROBERT M. GAVEDO, OF MIDDLEPORT, OHIO.

BRAKE HEAD AND SHOE.

To all whom it may concern:

Be it known that We, BENJAMIN F. IIY SELL and ROBERT M. CAvnoo, residingat Middleport, in the county of Meigs and State of Ohio, have inventedcertain new and useful Improvements in Brake Heads and Shoes, of whichthe following is a specification.

This invention is in the nature of an improved construction of brakehead and shoe for railway trucks, and other vehicles, and it has for itsobject to provide a shoe and head of the character stated, especiallydesigned for effecting an even wear throughout the length of the shoe toreduce the frequency with which the common type of brake shoes now ingeneral use have to be renewed.

I/Vith other objects in view that will here inafter appear, ourinvention consists in certain details of construction and peculiarcombination of parts,all of which will be hereinafter fully described,specifically pointed out in the claims and illustrated in theaccompanying drawing, in which:

Figure l, is a slde elevation of a car truck frame with our inventionattached, the shoes being shown in their applied or braking position.Fig. 2, is a similar view of one of the truck wheels and the brakedevices, the shoe being shown in the released position. Figs. 3 and 3are diagrams that illustrate respectively the relative position of thecommon type of brake shoes with respect to the wheel, and our form ofshoe, after having been worn. Fig. 4C, is a diagram of the shoehereinafter again referred to. Fig. 5, is a side elevation that showsthe brake shoe reversibly arranged to the showing in Fig.

2, to engage the front edge of the wheel, as

hereinafter more fully explained.

That the advantages of our invention may be readily understood, itshould be stated that in the present, general method of con struction ofbrake heads, it is common practice to connect the brake applying leverto the head in a position midway its ends so as to be intersected by aline that bisects and is normal to the chord of the arc of curvature ofthe wheel engaging face of the brake shoe. By this practice no adequateprovi sion is made for distributing the wear on the shoe. Theoreticallyif the engine or car ran as many miles backward as it runs forward thewear on the shoe would be compensated for, but as it is usual to run en-Speoification of Letters Patent.

Application filed October 7,- 1909.

Patented May 31, 1910.

Serial No. 521,523.

gines and cars in a given direction more miles than in an oppositedirection, such even distribution of wear does not take place with theresult that in practice one part of the shoe (usually the lower end) isworn away quicker than the remaining part of the shoe. lVhether the wearis greater on that part of the shoe below the connection of the headwith the hanger or above its point of connection will depend upon thelocation of the shoe with respect to the direction of turning of thewheel against which it engages. Vhen the construction shown in Fig. 3 isused and the wheel is normally running in a counterclockwise directionin such figure the greatest wear will be on the lower part of the shoeas that is the place of greatest pressure, whereas were the wheel ofFig. 8 rotating in a clockwise direction the greatest wear would be onthe upper part of the shoe for the same reason. Thus to overcome thisunequal wear on the shoe we have devised our improved brake head andmanner of applying the same to the wheel.

. In order to overcome the unequal wearing pressure on the curvedsurface of the shoe we move the oint of connection between the head andtie brake hanger beam to one side or the other of the imaginary linewhich bisects the chord of the arc of curvature and is normal thereto sothat if a line be drawn from the center of curvature of the wheel tobi-sect the chord of the arc of curvature of the shoe as shown in Fig.4, such line my 'will be normal to the chord 1"-s. Under the oldpractice the point of connection between the head 1 and the hanger Hwould be located at the point 3*, see Figs. 3 and 4, thereby resultingin the uneven wear on the shoe. In our construction we move the point ofconnection between the head 1 and the hanger H to one side or the otherof the line :n-y a distance suflicient that when a given force isapplied to the brake head the force of application of the brake shoe tothe wheel will be evenly distributed through the brake surface thereofto counterbalance the tendency of unequal wear. Thus it will be observedthat a line drawn between the center of the wheel (Q?) in Fig. 4 to thepoint 3 in Fig. 4 will make an angle other than 90 with the chord r-sand the angle 'z -w3 will depend upon the amount of pressure the systemis designed to operate under in applying the brakes and also upon thespeed of rotation of the Wheels, the object being to so proportion theangle that the tendency to greater wear at one end of the beam will becompensated by applying a correspondingly greater pressure at the other-end of the head and thereby reduce the pressure at the first end of thehead.

In the drawings, 1 designates the brake head, 2 the shoe, 3 the point ofconnection between the shoe and the brake applying lever hanger H. Thehanger H, as shown in the drawing, also performs the function of or actsas a brake applying lever.

4 is the pull lever that is actuated from the brake cylinder 6, in anyapproved manner and is connected by a rod 4* with the brake applyinglever hanger H.

The brake shoe 2 in our construction is preferably attached to the head1 by the bolts 1010 that pass at 12-12 through the brake head 1 and theinner projecting part of the shoe 2, (not shown), the bolts beingsecured by nuts 13, as shown.

The main purpose of our invention, as hereinbefore indicated, is to sohold the present type of brake shoe to the wheel that the wear on theshoe is evenly distributed, as shown by the dotted line as in Fig. 3 andto so cooperatively join the brake head 1 with the lever beam 1, thatthe shoe will be held with its rubbing face true and concentric with thewheel rim when the brake is applied, so that the force of actionresulting during the application of the brake to the wheel will be suchas to counteract the re-acting pressure due to the rotation of thewheel, sufiiciently to cause the active braking pressure along thesurface of contact to be evenly distributed at all points.

Another and important advantage in the practical application of ourinvention is that the brake head may be readily reversed so that it canbe used either behind or in front of the wheel, as indicated in Figs. 1and 5 of the drawings, but when used in front of the wheel the hangerand shoe are so held relatively to the wheel that the pull on the shoecaused by the rod a is in a line below the center of the shoe instead ofabove it, as in the case when the shoe is behind the wheel as indicatedin Figs. 1, 2, and 3 of the drawings.

By joining the shoe to the head as described, it can also be readilyreversed in the head if found desirable.

From the foregoing description taken in connection with the accompanyingdrawings, it is thought the completeconstruction, operation andadvantages of my invention will be readily understood by those skilledin the art to which the invention appertains.

\Vhat we claim is:

1. As an improvement in brakes, the combination with the car wheel, abrake head, a pivoted hanger, and means for connecting said hanger tosaid brake head, a removable shoe carried by said brake head, means formoving said hanger to bodily oscillate said shoe through an are havingas its center of curvature the pivotal point of said hanger, saidconnection between said brake head and said hanger being located at apoint outside of a line drawn normal to and bisecting the chord of thearc of curvature of the face of said shoe.

2. As an improvement in brakes, the combination with a car wheel, apivoted hanger, a brake head connected thereto to be swung in an arehaving as its center of curvature the pivot of said hanger, means foroperating said hanger to swing said brake head, a brake shoe carried bysaid brake head, the point of connection between said brake head andsaid hanger being such that when said brake shoe is in contact with thewheel rim a line drawn from the center of said wheel to bisect the chordof the arc of curvature of the face of the brake shoe will not passthrough the point of connection between such brake head and said hangerand that a line drawn between said point of connection of said brakehead with said hanger and the center of said wheel will make an anglewith said first mentioned line dependent upon the wearing force causedby the rot-ation of the wheel that is to be counteracted.

3. An improvement in brakes comprising the combination with the pivotedbrake applying member, of a brake head, a removable shoe carried by saidbrake head and a connection between said brake head and said brakeapplying member, said connection being located near one end of saidhead, substantially as shown and described.

BEN. F. HYSELL. R. lVL GAVEDO. W'itnesses:

JOHN B. YOUNG, Jr., WM. MICHAEL.

